The 2.1.1 version of Updraw for Mac was available to download on the developer's website when we last checked. We cannot confirm if there is a free download of this app available. The program belongs to Design & Photo Tools. Please check the Mac app with an antivirus before launch as it is downloaded from the developer's website, and we cannot ensure that it is safe. This free Mac application was originally created by Ben Blevins.
From the developer:
Updraw is a 2D CAD tool for your Mac. The application allows you to draw familiar shapes and add constraints to solve for unknown distances and angles. It comes with an intuitive interface designed specifically for 2D CAD constraint solving. The utility provides familiar 2D geometry: points, lines, circles, arcs, and cubic splines.
You may want to check out more Mac applications, such as Vectorworks 2010 Viewer, DropImageURL or Polaris, which might be similar to Updraw.